LED通信中利用蚁群算法优化光功率

Received optical power optimization based on ant colony algorithm for LED communications

室内可见光通信(VLC)的多光源阵列对称放置在房间的天花板上,光从LED光源出发经过直射、反射到达接收机端,在同一接收平面用户的接收光功率和照明强度不相等致使不能享受同等的通信服务质量,难以保证通信的公平性。针对通信系统中光源放置位置导致接收平面的接收光功率和照明强度分布由房间中心向周围快速衰减的问题,通过在4×4LED发射阵列端配备功率调节因子,利用蚁群算法建立与接收光功率和照明强度相对应的节点和路径的模型,提出使用方差作为评价接收光功率和照明强度均匀化的目标函数,构建能见度表达式据此推导出状态转移概率公式,并根据LED发射阵列和接收机位置对称的要求选取一组优化功率调节因子值。仿真结果表明,接收光功率和照明强度的方差分别从优化前的168 252和653 742降低到优化后的19.266 3和74.859 2,接收平面接收光功率和照明强度分布不均匀性得到明显改善。

Because in indoor visible light communication（VLC）multiple light sources in array are symmetrically placed on the ceiling of the room,light travels from the light source to the receiver through the direct light and reflection.The user receiving light power and illumination intensity of the same receiving plane are not equal,so it is difficult to ensure the fairness of communication.In the indoor visible light communication system,light source position leads to the problem of the distributions of receiving light power and illumination intensity which fast decay from center to edge.To solve the problem we equip the4×4LED array transmitter with power adjustment factor,take advantage of ant colony algorithm to model the nodes and paths of receiving light power and illumination intensity,and then set variance as the objective function to evaluate homogenization.Based on the established visibility equations,we deduce probability equations of state transition.Finally,according to symmetrical positions of LED emitter array and receiver,we select a set of optimized power adjustment factors.The simulation results show that the variance of receiving light power decreases from 168252 to 19.2663 and illumination intensity decreases from 653724 to 74.859 2,which improves the uneven distribution significantly.Hence,the method proposed in this paper can optimize power coverage and improve the service quality of indoor LED communications.